Question

$(l + m) {}^{2} - 4lm$

Answer 1

Hlo

here is ur answer...

( l + m )² - 4lm

(a+b)² = a² + b² + 2ab


➡( l² + m² + 2lm ) - 4lm

➡l² + m² + 2lm - 4lm

➡l² + m² - 2lm

(l - m )²✔

Answer 2

( l + m )² - 4lm

$<b>( a + b )² = a² + b² + 2ab</b>$

= l² + m² + 2 ( l ) ( m ) - 4lm

= l² + m² + 2lm - 4lm

= l² + m² - 2lm

= ( l )² + ( m )² - 2 ( l ) ( m )

$<b>a² + b² - 2ab = ( a - b )²</b>$

= $<b><u>( l - m )²</b></u>$

Also, there is a direct identity –

$<i>( a + b )² - 4ab = ( a - b )²</i>$